Late spring at StarChefs.com always means an editorial sweep across New York City, harvesting material for the upcoming editorial calendar year and tasting with candidates for our 2009 Rising Stars. We attended events and tastings armed with Flip video cameras, and the second the shakers were sealed, we started filming, regardless of how dark or loud the bar was. The result is a compendium of shaking styles that reflects work histories, philosophies, personalities—even blood alcohol levels at the time of shooting.

There are three physical factors at work in a well-made cocktail: water content, ingredient distribution and temperature. While some spirits require only a stir to achieve a balance of these factors, others can only attain true cocktail Nirvana with a shake. And, as we learned, a mixologist's shake is like a thumbprint—no two shakes are the same.

According to Joaquin Simo of New York City’s Death & Company, “A shake should wake up a cocktail. Its function is to make it greater than the sum of its parts.” For Simo, shaking is necessary to combine different textures into one.

What types of cocktails need shaking? “Any drink that contains an element that can cloud up a drink,” says 2007 New York Rising Star Jim Meehan of PDT, citing citrus, egg whites and cream as the most commonly shaken ingredients.

The theory behind the shake holds that the back-and-forth motion drives an ice cube to chip at the corners, breaking off bits that dilute and chill the liquid. The remaining chunks of ice further chill the liquid as the cocktail becomes aerated and blended.

Mixologists agree that different cocktails call for different shakes. Recipes call for varying levels of dilution and temperature, depending on how they are to be consumed. A shaken cocktail served up should get a long and hard shake in order to achieve a nice, frothy consistency, as it won’t have ice to keep it cold. Conversely, for drinks served on ice, the shake should be modified accordingly. In the end, it's about what you’re trying to achieve with the cocktail.

Albert Trummer of New York’s Apothéke suggests always using the proper proportions of ice and liquid inside a shaker. That means not too much of either, and no shaking more than two drinks’ worth of alcohol in one tumbler. Shaking should stop when the metal is near frozen.

Things get more complicated when you take into account the different types of ice and the process used to make them. On our tastings across the country, we've seen a little bit of everything, from 300-pound slabs of industrial ice broken down with ice picks to house-made ice cubes carved into diamonds with sashimi knives. Premium ice machines like those manufactured by Kold-Draft have also become a popular tool for bars that are serious about their cocktail program.

At Little Branch in New York City, ice is a matter of preference—Mixologist and 2008 New York Rising Star Sam Ross uses single in-house frozen blocks of ice. “It has to be as efficient as possible” Ross says. “You want maximum chill with minimal dilution”.

At Long Island City, NY, bar Dutch Kills, Giuseppe Gonzalez and co-owner Richard Boccato replace the usual mixing glass with a smaller metal tumbler to obtain a better seal on cocktails and a colder temperature.

Also, without the metal tumbler, the slow-frozen block ice used at Dutch Kills would simply shatter any mixing glass, especially considering the brute force of certain shakes like Gonzalez's or Brian Miller at Death & Company. If using a mixing glass, double-tempered bottoms are a must.

“Function begets form,” says Back Forty’s Michael Cecconi. The New York mixologist’s high shaking style evolved from the need to avoid colliding with servers and managers passing through the bar during service. Apothéke's Miguel Aranda cautiously shakes to the side to avoid spraying patrons should the seal break.

As anyone would expect, shaking 200 cocktails a night can cause significant wear on a person’s body. Mixologist Alex Day of Death & Company adopted his style as a variation on the hard shake, modified to protect him from shaking-related injuries he’s seen occur to colleagues. At Apothéke, Orson Salicetti adopts a martial arts-inspired stance to protect his back.

All shaking technicalities aside, mixologists will always be front-of-the-house employees, at the service of his/her guests. Where cocktails are taken seriously, the shake itself is an integral part of the entertainment factor in the dining/drinking experience. “A shake should be pleasant to watch,” as Meehan puts it. And he’s right. Regardless of how hard the shake is, or who is shaking the drink, patrons will always turn their heads when they hear the familiar "ka-chunk, ka-chunk" sound sailing out from behind the bar.